I have run the Screaming Eagle Race Fueler, and I have had a couple Power Commanders.
The race fueler is a good concept. Great if you have a tach on the bike and or a good ear for tuning the motor. Pretty easy installation popped off the seat on my softail. Removed the rear tank bolt, and propped up the end of the tank to make room to get to the injectors. Total install time under 30 minutes from start to finish.
Price was $225, required no dyno time.
Has three "pots" low,mid,high. Also has two screws to control when the mid and high "pots" take effect. Also has a 6th adjustment for adding fuel to fast open throttle acceleration. Good for taking hesitation out of the bike.
However, after less than two years of use. It has recently stopped working. Which totally sucked, because A.) I didn't have a toolbox strapped on the bike, and B.) pushing a motorcycle down the street can be hard uphill. I then went to the dealer to get a replacement, to come home and open the box to find a unit that had loose wires in one of the tie in EFI connectors and pieces of the insulation in the wiring harness stripped. Upon trying to return the unit (that I just bought mind you) and getting a bunch of gruff on how they don't take returns on electrcal parts. I have decided to go another route. Still to be determined, but most likely a power commander.
The Power Commander. I have run 2 of these. Both have been on my sport bikes.
The power commander used to be around $350, but I just picked one up for $280 for my new bike.
These are more "new school" tuner friendly. Doesn't require a tach or an ear for the setup. Maps are readily available for download from their website. A laptop makes setup of these a snap. Installation time took a little longer on these, but I had to remove more body parts and find a good mounting spot for ease of USB hookup. The front of the unit still has the low,mid,high "pot" adjustments that can be used to dail it in.
I have never had a dyno to set these up, and I can't complain about the performance. I'm sure a dyno tune could probably squeeze a few more ponies out of a bike here or there, but I don't know that the cost is justified, and I like to tinker anyway.
I decided on both of these units for their plug and play design. I went with the SERF to try and keep the bike all screaming eagle, but I have recently changed my mind on that. My choice on the power commander had to do with add on's they have, quick shift, ignition module etc.
When I get in my new unit for the softail, I will post the install and setup with some pic's.